Cleanup: Modify GitHub Actions and content so all data examples come from their source-of-truth repos

[emmambd]

Feature request

Is your feature request related to a problem? Please describe.
gtfs.org is automatically generated from a variety of different Github repos, thus ensuring we're respecting the governance process for the different specifications (GTFS Schedule vs. GTFS Best Practices) and consolidating the documentation for different open source tools (real time language bindings, the Awesome Transit list). The idea is that you should be able to find everything you need to know about GTFS on gtfs.org in one place, and that it's as up to date as possible thanks to the automatic updates from their original source-of-truth repos.

(Quick visual mapping here)

But right now, we have a mix of data examples that live on the gtfs.org repo and ones that live on the transit repo. The original intent was that all examples lived on the transit repo. We should update this to reflect the original intention.

Proposed solution
There's a couple key components to this:

• Create issue templates (one including example changes), so it's clear what's required of contributors to improve the example documentation
• Create a PR to add all the data examples over in transit
• Update GitHub Actions so we're pulling examples from the transit repo.